Lamb wave element and bulk acoustic wave resonator on common substrate

ABSTRACT

Aspects of this disclosure relate to an acoustic wave device that includes a bulk acoustic wave resonator and a Lamb wave element implemented on a common substrate. In some instances, the bulk acoustic wave resonator can be a film bulk acoustic wave resonator. Related radio frequency modules and wireless communication devices are disclosed.

CROSS REFERENCE TO PRIORITY APPLICATION

This application claims the benefit of priority under 35 U.S.C. § 119(e)of U.S. Provisional Patent Application No. 62/637,641, filed Mar. 2,2018 and titled “LAMB WAVE LOOP CIRCUIT FOR ACOUSTIC WAVE FILTER,” thedisclosure of which is hereby incorporated by reference in its entiretyherein.

BACKGROUND Technical Field

Embodiments of this disclosure relate to acoustic wave filters.

Description of Related Technology

Acoustic wave filters can filter radio frequency signals. An acousticwave filter can include a plurality of resonators arranged to filter aradio frequency signal. The resonators can be arranged as a laddercircuit. Example acoustic wave filters include surface acoustic wave(SAW) filters, bulk acoustic wave (BAW) filters, and Lamb wave resonatorfilters. A film bulk acoustic resonator (FBAR) filter is an example of aBAW filter. A solidly mounted resonator (SMR) filter is another exampleof a BAW filter.

Acoustic wave filters can be implemented in radio frequency electronicsystems. For instance, filters in a radio frequency front end of amobile phone can include acoustic wave filters. Two acoustic wavefilters can be arranged as a duplexer.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of the claims, some prominent features ofthis disclosure will now be briefly described.

One aspect of this disclosure is an acoustic wave device that includesan acoustic wave filter configured to filter a radio frequency signaland a loop circuit coupled to the acoustic wave filter. The loop circuitis configured to generate an anti-phase signal to a target signal at aparticular frequency. The loop circuit including a Lamb wave element.

The acoustic wave filter can include can include a bulk acoustic waveresonator. The bulk acoustic wave resonator and the Lamb wave elementcan each include the same piezoelectric material. The piezoelectricmaterial can be aluminum nitride. The bulk acoustic wave resonator andthe Lamb wave element can share a cavity. The bulk acoustic waveresonator and the Lamb wave element can have separate cavities. The bulkacoustic wave resonator can be a film bulk acoustic resonator.

The acoustic wave filter can include can include a surface acoustic waveresonator. The acoustic wave filter can include a Lamb wave resonator.The acoustic wave filter can be a receive filter. The acoustic wavefilter can be a transmit filter.

The Lamb wave element can include an aluminum nitride layer. The Lambwave element can include a lithium niobate layer. The Lamb wave elementcan include a lithium tantalate layer. The Lamb wave element can includean interdigital transducer electrode on a piezoelectric layer andgratings disposed on the piezoelectric layer on opposing sides of theinterdigital transducer electrode. The Lamb wave element can include aninterdigital transducer electrode on a piezoelectric layer, in which theinterdigital transducer electrode has free edges. The Lamb wave elementcan operate in one or more of a lowest-order asymmetric mode, alowest-order symmetric mode, a lowest-order shear horizontal mode, afirst-order asymmetric mode, a first-order symmetric mode, or afirst-order shear horizontal mode.

The Lamb wave element and at least one resonator of the acoustic wavefilter can be on a common semiconductor substrate. The semiconductorsubstrate can be a silicon substrate.

The acoustic wave device can further include a second acoustic wavefilter, in which the acoustic wave filter and the second acoustic wavefilter are included in a duplexer.

Another aspect of this disclosure is a radio frequency module thatincludes a duplexer and a radio frequency switch. The duplexer includesan acoustic wave device. The acoustic wave device includes an acousticwave filter and a loop circuit coupled to the acoustic wave filter. Theloop circuit is configured to generate an anti-phase signal to a targetsignal at a particular frequency. The loop circuit includes a Lamb waveelement. The radio frequency switch is arranged to pass a radiofrequency signal associated with a port of the duplexer.

The acoustic wave filter can include a film bulk acoustic waveresonator. The film bulk acoustic wave resonator and the Lamb waveelement can be on a common substrate. The common substrate can be asilicon substrate. The Lamb wave element can include an aluminum nitridelayer.

The radio frequency module can further include a power amplifier, inwhich the radio frequency switch coupled in a signal path between thepower amplifier and the duplexer.

The radio frequency switch can be an antenna switch, and the port of theduplexer can be an antenna port coupled to the radio frequency switch.

Another aspect of this disclosure is a wireless communication devicethat includes a radio frequency front end and an antenna incommunication with the radio frequency front end. The radio frequencyfront end includes an acoustic wave device. The acoustic wave deviceincludes an acoustic wave filter configured to filter a radio frequencysignal and a loop circuit coupled to the acoustic wave filter. The loopcircuit configured to generate an anti-phase signal to a target signalat a particular frequency. The loop circuit includes a Lamb waveelement.

The acoustic wave filter can includes a film bulk acoustic waveresonator. The film bulk acoustic wave resonator and the Lamb waveelement can be on a common silicon substrate.

Another aspect of this disclosure is an acoustic wave device thatincludes a bulk acoustic wave resonator and a Lamb wave element. Thebulk acoustic wave resonator includes a piezoelectric layer positionedbetween a first electrode and a second electrode. The bulk acoustic waveresonator and the Lamb wave element are implemented on a commonsubstrate of a die.

The acoustic wave device can further include additional bulk acousticwave resonators on the common substrate. The bulk acoustic waveresonator and the additional bulk acoustic wave resonators can beincluded in a band pass filter. The band pass filter can be arranged tofilter a radio frequency signal. The Lamb wave element can be includedin a loop circuit that is coupled to the band pass filter. The loopcircuit can be configured generate an anti-phase signal to a targetsignal at a particular frequency.

The bulk acoustic wave resonator can be a film bulk acoustic resonator.The common substrate can include silicon. The Lamb wave element caninclude a piezoelectric layer that includes the same material as apiezoelectric layer of the bulk acoustic wave resonator. The materialcan include aluminum nitride. The bulk acoustic wave resonator and theLamb wave element can share a cavity. The bulk acoustic wave resonatorand the Lamb wave element can have separate cavities.

The bulk acoustic wave resonator can be a solidly mounted resonator. TheLamb wave element can include a Bragg reflector.

The Lamb wave element can include an interdigital transducer electrodeon a piezoelectric layer and gratings disposed on the piezoelectriclayer on opposing sides of the interdigital transducer electrode. TheLamb wave element can include an interdigital transducer electrode on apiezoelectric layer, in which the interdigital transducer electrode hasfree edges.

Another aspect of this disclosure is a radio frequency module thatincludes an acoustic wave device and a radio frequency switch. Theacoustic wave device includes a Lamb wave element and a bulk acousticwave resonator. The bulk acoustic wave resonator and the Lamb waveelement are implemented on a common substrate of a die. The bulkacoustic wave resonator is included in a band pass filter arranged tofilter a radio frequency signal. The radio frequency switch is coupledto the band pass filter. The radio frequency switch is arranged to passthe radio frequency signal.

The bulk acoustic wave resonator can be a film bulk acoustic waveresonator. The common substrate can be a silicon substrate. The Lambwave element can include an aluminum nitride layer.

Another aspect of this disclosure is a wireless communication devicethat includes a radio frequency front end and an antenna. The radiofrequency front end includes an acoustic wave device. The acoustic wavedevice includes a Lamb wave element and a bulk acoustic wave resonator.The Lamb wave element and the bulk acoustic wave element are implementedon a common substrate of a die. The bulk acoustic wave resonator isincluded in a band pass filter arranged to filter a radio frequencysignal. The antenna in communication with the band pass filter.

The bulk acoustic wave resonator can be a film bulk acoustic waveresonator. The common substrate can be a silicon substrate. The Lambwave element can include an aluminum nitride layer.

Another aspect of this disclosure is an acoustic wave filter thatincludes a Lamb wave resonator and a second acoustic wave resonatorelectrically coupled to the Lamb wave resonator. The second acousticwave resonator is a different type of acoustic wave resonator than theLamb wave resonator. The acoustic wave filter configured to filter aradio frequency signal.

The Lamb wave resonator and the second acoustic wave resonator can beimplemented on a common substrate of a die. The common substrate can bea silicon substrate. The Lamb wave resonator can include a piezoelectriclayer that includes the same material as a piezoelectric layer of thesecond acoustic wave resonator. The piezoelectric layer of the Lamb waveresonator can be an aluminum nitride layer.

The second acoustic wave resonator can be a film bulk acoustic waveresonator. The Lamb wave resonator and the film bulk acoustic waveresonator can share a cavity. The Lamb wave resonator and the film bulkacoustic wave resonator can include separate cavities.

The second acoustic wave resonator can be a surface acoustic waveresonator.

The Lamb wave resonator can be a series resonator and the secondacoustic wave resonator can be a shunt resonator. The Lamb waveresonator can be a shunt resonator and the second acoustic waveresonator can be a series resonator.

The acoustic wave filter can further include a plurality of additionalacoustic wave resonators. The additional acoustic wave resonators can bethe same type of acoustic wave resonator as the second acoustic waveresonator.

The acoustic wave filter can include a first number of acoustic waveresonators that are the same type of acoustic wave resonator as thesecond acoustic wave resonator, in which the first number being at leasttwice as many as a second number of one or more Lamb wave resonators ofthe acoustic wave filter.

Another aspect of this disclosure is a wireless communication devicethat includes an acoustic wave filter and an antenna in communicationwith the acoustic wave filter. The acoustic wave filter is configured tofilter a radio frequency signal. The acoustic wave filter includes aLamb wave resonator and a second of acoustic wave resonator. The Lambwave resonator and the second acoustic wave resonator are implemented ona common substrate. The second acoustic wave resonator is a differenttype of acoustic wave resonator than the Lamb wave resonator;

The second type of acoustic wave resonator can be a film bulk acousticwave resonator, and the Lamb wave resonator can include a piezoelectriclayer that includes the same material as a piezoelectric layer of thefilm bulk wave resonator.

Another aspect of this disclosure is an acoustic wave filter assemblythat includes a first acoustic wave filter and a second acoustic wavefilter. The first acoustic wave filter is configured to filter a firstradio frequency signal. The first acoustic wave filter includes a Lambwave resonator implemented on a substrate of a die. The second acousticwave filter is configured to filter a second radio frequency signal. Thesecond acoustic wave filter including an acoustic wave resonatorimplemented on the same substrate of the die as the Lamb wave resonator.The acoustic wave resonator is a different type of acoustic waveresonator than the Lamb wave resonator.

The acoustic wave resonator can be a film bulk acoustic wave resonator.The Lamb wave resonator can include a piezoelectric layer that includesthe same material as a piezoelectric layer of the acoustic waveresonator.

The first acoustic wave filter and the second acoustic wave filter canbe e coupled together at a common node of a multiplexer. The multiplexercan be a duplexer.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

The present disclosure relates to U.S. patent application Ser. No.16/287,802, titled “LAMB WAVE LOOP CIRCUIT FOR ACOUSTIC WAVE FILTER,”filed on even date herewith, the entire disclosure of which is herebyincorporated by reference herein. The present disclosure relates to U.S.patent application Ser. No. 16/287,909, titled “LAMB WAVE RESONATOR ANDOTHER TYPE OF ACOUSTIC WAVE RESONATOR INCLUDED IN ONE OR MORE FILTERS”filed on even date herewith, the entire disclosure of which is herebyincorporated by reference herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1A is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a film bulk acoustic resonator (FBAR)on a common substrate according to an embodiment.

FIG. 1B is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and an FBAR on a common substrate accordingto another embodiment.

FIG. 1C is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and an FBAR on a common substrate accordingto another embodiment.

FIG. 1D is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and an FBAR on a common substrate accordingto another embodiment.

FIG. 2 is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a solidly mounted resonator (SMR) on asubstrate according to an embodiment.

FIG. 3A is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a surface acoustic wave (SAW) resonatorof an acoustic on a common substrate according to an embodiment.

FIG. 3B is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a SAW resonator of an acoustic on acommon substrate according to another embodiment.

FIG. 4A is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a Lamb wave resonator on a commonsubstrate according to an embodiment.

FIG. 4B is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a Lamb wave resonator on a commonsubstrate according to another embodiment.

FIG. 5A is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a solidly mounted Lamb wave resonatoron a common substrate according to an embodiment.

FIG. 5B is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a solidly mounted Lamb wave resonatoron a common substrate according to another embodiment.

FIG. 5C is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a solidly mounted Lamb wave resonatoron a common substrate according to another embodiment.

FIG. 5D is a diagram of cross section of an acoustic wave device thatincludes a Lamb wave element and a solidly mounted Lamb wave resonatoron a common substrate according to another embodiment.

FIG. 6 is a diagram of cross section of an acoustic wave device thatincludes a solidly mounted Lamb wave element and an FBAR on a commonsubstrate according to an embodiment.

FIG. 7 is a diagram of cross section of an acoustic wave device thatincludes a solidly mounted Lamb wave element and an SMR on a commonsubstrate according to an embodiment.

FIG. 8 is a diagram of cross section of an acoustic wave device thatincludes a solidly mounted Lamb wave element and a SAW resonator on acommon substrate according to an embodiment.

FIG. 9 is a diagram of cross section of an acoustic wave device thatincludes a solidly mounted Lamb wave element and a Lamb wave resonatoron a common substrate according to an embodiment.

FIG. 10 is a diagram of cross section of an acoustic wave device thatincludes a solidly mounted Lamb wave element and a solidly mounted Lambwave resonator on a common substrate according to an embodiment.

FIGS. 11A to 11F are diagrams of cross sections of Lamb wave elementswith gratings. FIG. 11A illustrates a Lamb wave element with a groundedelectrode. FIG. 11B illustrates a Lamb wave element with a floatingelectrode. FIG. 11C illustrates a Lamb wave element without an electrodeon a side of a piezoelectric layer that opposes an interdigitaltransducer (IDT) electrode. FIG. 11D illustrates another Lamb waveelement. FIG. 11E illustrates another Lamb wave element. FIG. 11Fillustrates another Lamb wave element.

FIGS. 12A to 12F are diagrams of cross sections of Lamb wave elementswith free edges. FIG. 12A illustrates a Lamb wave element with agrounded electrode. FIG. 12B illustrates a Lamb wave element with afloating electrode. FIG. 12C illustrates a Lamb wave element without anelectrode on a side of a piezoelectric layer that opposes an IDTelectrode. FIG. 12D illustrates another Lamb wave element. FIG. 12Eillustrates another Lamb wave element. FIG. 12F illustrates another Lambwave element.

FIG. 13 is a schematic diagram of a duplexer with a loop circuit for atransmit filter according to an embodiment.

FIG. 14 is a graph comparing isolation for the duplexer of FIG. 13 to acorresponding duplexer without a loop circuit.

FIG. 15 is a schematic diagram of a duplexer with a loop circuit for areceive filter according to an embodiment.

FIG. 16A is a graph comparing isolation for the duplexer of FIG. 15 to acorresponding duplexer without a loop circuit.

FIG. 16B is a graph comparing receive band rejection for the duplexer ofFIG. 15 to a corresponding duplexer without a loop circuit.

FIG. 17 is a schematic diagram of a duplexer with a first loop circuitfor a transmit filter and a second loop circuit for a receive filteraccording to an embodiment.

FIG. 18 is a graph comparing isolation for the duplexer of FIG. 17 to acorresponding duplexer without loop circuits.

FIG. 19 is a schematic diagram of a duplexer with a loop circuit coupledbetween a transmit port of a transmit filter and a receive port of areceive filter according to an embodiment.

FIG. 20 is a schematic diagram of an acoustic wave filter assembly thatincludes a first filter with a Lamb wave resonator and a second filterwith a different type of acoustic wave resonator, in which the Lamb waveresonator and the different type of resonator are implemented on thesame substrate according to an embodiment.

FIG. 21A is a schematic diagram of an acoustic wave filter that includesseries Lamb wave resonators and other shunt acoustic wave resonatorsaccording to an embodiment.

FIG. 21B is a schematic diagram of an acoustic wave filter that includesshunt Lamb wave resonators and other series acoustic wave resonatorsaccording to an embodiment.

FIG. 21C is a schematic diagram of an acoustic wave filter that includesa series Lamb wave resonator and other acoustic wave resonators coupledto an antenna port via the series Lamb wave resonator according to anembodiment.

FIG. 21D is a schematic diagram of an acoustic wave filter that includesa series Lamb wave resonator and other acoustic wave resonators coupledto a radio frequency port via the series Lamb wave resonator accordingto an embodiment.

FIG. 21E is a schematic diagram of an acoustic wave filter that includesa series Lamb wave resonator and other acoustic wave resonatorsaccording to an embodiment.

FIG. 21F is a schematic diagram of an acoustic wave filter that includesa shunt Lamb wave resonator and other acoustic wave resonators accordingto an embodiment.

FIG. 22A is a schematic block diagram of a module that includes anantenna switch and a duplexer with a Lamb wave loop circuit according toan embodiment.

FIG. 22B is a schematic block diagram of a module that includes anantenna switch and a plurality of filters with a Lamb wave loop circuitaccording to an embodiment.

FIG. 22C is a schematic block diagram of a module that includes a poweramplifier, a switch, and a duplexer with a Lamb wave loop circuitaccording to an embodiment.

FIG. 22D is a schematic block diagram of a module that includes poweramplifier, a switch, a duplexer with a Lamb wave loop circuit, and anantenna switch according to an embodiment.

FIG. 23A is a schematic block diagram of a module that includes anantenna switch and one or more filters that include a Lamb waveresonator and another type of acoustic wave resonator according to anembodiment.

FIG. 23B is a schematic block diagram of a module that includes a poweramplifier, a switch, and one or more filters that include a Lamb waveresonator and another type of acoustic wave resonator according to anembodiment.

FIG. 23C is a schematic block diagram of a module that includes poweramplifier, a switch, one or more filters that include a Lamb waveresonator and another type of acoustic wave resonator, and an antennaswitch according to an embodiment.

FIG. 24 is a schematic block diagram of a wireless communication devicethat includes a filter with a lamb wave element according to anembodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following description of certain embodiments presents variousdescriptions of specific embodiments. However, the innovations describedherein can be embodied in a multitude of different ways, for example, asdefined and covered by the claims. In this description, reference ismade to the drawings where like reference numerals can indicateidentical or functionally similar elements. It will be understood thatelements illustrated in the figures are not necessarily drawn to scale.Moreover, it will be understood that certain embodiments can includemore elements than illustrated in a drawing and/or a subset of theelements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

An acoustic wave filter can include a loop circuit to cancel an unwantedfrequency component. The loop circuit can enhance transmit/receiveisolation and attenuation for a particular frequency range. The loopcircuit can apply a signal having approximately the same amplitude andan opposite phase to a signal component to be canceled. Surface acousticwave (SAW) loops circuits have been used to suppress isolation andattenuation in SAW filters. Some loop circuits for film bulk acousticresonator (FBAR) filters and other bulk acoustic wave (BAW) filters haveincluded LC circuits. Such LC circuits can include capacitor(s) and/orinductor(s) having a relatively large physical footprint and/or can beimplemented external to a chip that includes the BAW filter coupled tothe loop circuit.

Lamb wave loop circuits are disclosed. Lamb wave loop circuits can beintegrated with BAW filters and/or duplexers. For instance, aluminumnitride (AlN) Lamb wave loop circuits can be integrated with aluminumnitride FBAR filters. Such Lamb wave loop circuits can suppresstransmit/receive (Tx/Rx) isolation and attenuation at any desiredfrequency range. A Lamb wave loop circuit can generate an anti-phaseradio frequency (RF) signal to cancel a target signal at a desiredfrequency. The Lamb wave loop circuits discussed herein can improve theisolation and attenuation of RF acoustic wave filters, such as BAWfilters (e.g., FBAR filters or SMR filters), SAW filters, and Lamb wavefilters.

A Lamb wave element can be a Lamb wave resonator or a Lamb wave delayline. A Lamb wave element can combine features of a SAW element and aBAW element. A Lamb wave resonator typically includes an interdigitaltransducer (IDT) electrode similar to a SAW resonator. Accordingly, thefrequency of the Lamb wave resonator can be lithographically defined. ALamb wave element can achieve a relatively high quality factor (Q) and arelatively high phase velocity like a BAW filter. The relatively high Qof a Lamb wave resonators can be due to, for example, a suspendedstructure. A Lamb wave element that includes an aluminum nitridepiezoelectric layer can be relatively easy to integrate with othercircuits, for example, because aluminum nitride process technology canbe compatible with complementary metal oxide semiconductor (CMOS)process technology. Aluminum nitride Lamb wave resonators can overcome arelatively low resonance frequency limitation and integration challengeassociated with SAW resonators and also overcome multiple frequencycapability challenges associated with BAW resonators. Some Lamb waveresonator topologies are based on acoustic reflection from periodicreflective gratings. Some other Lamb wave resonator topologies are basedon acoustic reflection from suspended free edges of a piezoelectriclayer.

A Lamb wave loop circuit and a BAW resonator of an acoustic wave filtercan be implemented on a common substrate. An aluminum nitride Lamb waveloop circuit can be directly integrated with aluminum nitride FBARfilter and/or other BAW filters during processing to form such filters.Such integration can also be achieved for other suitable piezoelectricfilms. Accordingly, a Lamb wave loop circuit can have offer a costeffective and efficient way to include a loop circuit for a BAW filter.A Lamb wave loop circuit integrated with a BAW filter can bemanufactured with characteristics sufficient for a loop circuit in acost effective manner. A Lamb wave loop circuit for a BAW filter can beimplemented in a relatively small physical footprint. For example, aLamb wave loop circuit can have a smaller physical footprint than an LCcircuit based loop circuit. A smaller physical footprint can reducepower consumption and/or reduce manufacturing costs.

Lamb wave elements in a loop circuit discussed herein can operate in anysuitable acoustic wave mode. Example acoustic wave modes that can beutilized in Lamb wave elements discussed herein include the lowest-orderasymmetric (A₀) mode, the lowest-order symmetric (S₀) mode, thelowest-order shear horizontal (SH₀) mode, the first-order asymmetric(A₁) mode, the first-order symmetric (S₁) mode, the first-order shearhorizontal (SH₁) mode, the second-order asymmetric (A₂) mode, thesecond-order symmetric (S₂) mode, the second-order shear horizontal(SH₂) mode, and the like.

A Lamb wave element and a different type of acoustic wave resonator canbe implemented on the same substrate of a die. The Lamb wave element canbe included in a loop circuit and the different element can be in anacoustic wave filter coupled to the loop circuit. A Lamb wave elementcan a different type of acoustic wave element on a common substrate canbe implemented in a variety of other applications. In certain instances,an acoustic wave filter can include a Lamb wave resonator and adifferent type of acoustic wave resonator implemented on the same die.For example, an acoustic wave filter can include a Lamb wave resonatorand an FBAR implemented on a common substrate. According to certainapplications, a first acoustic wave filter can include a Lamb waveresonator and a second acoustic wave filter can include a different typeof acoustic wave resonator, in which the Lamb wave resonator and thedifferent type of acoustic wave resonator are implemented on a commonsubstrate.

A loop circuit can include a free-standing Lamb wave element. Forexample, such a Lamb wave element and a resonator of an acoustic wavefilter coupled to the loop circuit can be implemented in accordance withany suitable principles and advantages of the acoustic wave devices ofFIGS. 1A to 5D. The acoustic wave devices of FIGS. 1A to 5D can also beimplemented in other applications. Any suitable combination of featuresof the acoustic wave devices of FIGS. 1A to 5D can be implementedtogether with each other.

FIG. 1A is a diagram of cross section of an acoustic wave device 10 thatincludes a film bulk acoustic resonator (FBAR) 12 and a Lamb waveelement 14 according to an embodiment. The FBAR 12 and the Lamb waveelement 14 are implemented on a common substrate 19. The FBAR 12 can beincluded in an acoustic wave filter and the Lamb wave element 14 can beincluded in a loop circuit. The FBAR 12 includes electrodes 13A and 13Bon opposing sides of a piezoelectric substrate 15. The Lamb wave element14 can be a Lamb wave resonator in certain instances. A Lamb waveresonator is a type of acoustic wave resonator. The Lamb wave element 14can be a delay line in some instances. A Lamb wave delay line caninclude two sets of interdigital transducers.

The Lamb wave element 14 includes feature of a SAW resonator and anFBAR. As illustrated, the Lamb wave element 14 includes a piezoelectriclayer 15, an interdigital transducer electrode (IDT) electrode 16 on thepiezoelectric layer 15, and an electrode 17. The piezoelectric layer 15can be a thin film. The piezoelectric layer 15 can be an aluminumnitride layer. In other instances, the piezoelectric layer 15 can be anysuitable piezoelectric layer. For example, the piezoelectric layer 15can be a lithium niobate layer or a lithium tantalate layer. Thefrequency of the Lamb wave resonator can be based on the geometry of theIDT electrode 16. In some instances, the illustrated IDTs of the Lambwave element 14 represent two sets of IDTs. The electrode 17 can begrounded in certain instances. In some other instances, the electrode 17can be floating. An air cavity 18 is disposed between the electrode 17and a substrate 19. Any suitable cavity can be implemented in place ofthe air cavity 18. The substrate 19 can be a semiconductor substrate.For example, the substrate 19 can be a silicon substrate. The substrate19 can be any other suitable substrate, such as a quartz substrate, asapphire substrate, or a spinel substrate.

In the acoustic wave device 10, the Lamb wave resonator 14 and the FBAR12 share a piezoelectric layer 15. A first portion of the piezoelectriclayer 15 can be considered the piezoelectric layer of the FBAR 12 and asecond portion of the piezoelectric layer 15 can be considered thepiezoelectric layer of the Lamb wave element 14. As also illustrated inFIG. 1A, the Lamb wave resonator 14 and the FBAR share an air cavity 18.In certain applications, sharing an air cavity 18 can reduce the size ofan acoustic wave device relative to implementing separate air cavities.The Lamb wave resonator 14 and the FBAR 12 can be disposed on a commonsemiconductor substrate 19. The semiconductor substrate 19 can be asilicon substrate.

FIG. 1B is a diagram of cross section of an acoustic wave device 10′that includes an FBAR 12′ and a Lamb wave element 14′ according to anembodiment. The acoustic wave device 10′ is like the acoustic wavedevice 10 of FIG. 1A except that separate air cavities 18A and 18B areincluded in the acoustic wave device 10′ for the FBAR 12′ and the Lambwave element 14′, respectively. In the acoustic wave device 10′, a firstair cavity 18A is provided for the FBAR 12′ and a second air cavity 18Bis provided for the Lamb wave element 14′. In certain instances, havingseparate air cavities can be beneficial for maintaining the mechanicalintegrity of the acoustic wave device 10′ and/or reducing cross talkbetween the FBAR 12 and the Lamb wave element 14.

FIG. 1C is a diagram of cross section of an acoustic wave device 10″that includes an FBAR 12″ and a Lamb wave element 14″ according to anembodiment. The acoustic wave device 10″ is like the acoustic wavedevice 10 of FIG. 1A except that an air cavity is implemented in thesubstrate 19′ instead of over the substrate 19 of FIG. 1A. An air cavity18′ can be implemented for the acoustic wave device 10″ by etching aportion of the substrate 19′.

FIG. 1D is a diagram of cross section of an acoustic wave device 10′″that includes an FBAR 12′″ and a Lamb wave element 14′″ according to anembodiment. The acoustic wave device 10′″ is like the acoustic wavedevice 10′ of FIG. 1B except that air cavities are implemented in thesubstrate 19″ instead of over the substrate 19 of FIG. 1B. The aircavities 18A′ and 18B′ can be implemented for the acoustic wave device10′″ by etching portions of the substrate 19″.

FIG. 2 is a diagram of cross section of an acoustic wave device 20 thatincludes a Lamb wave element 14 and a solidly mounted resonator (SMR) 22according to an embodiment. In the acoustic wave device 20, the SMR 22and the Lamb wave element 14 are implemented on a common substrate 19.The SMR 22 can be included in an acoustic wave filter and the Lamb waveelement 14 can be included in a loop circuit. The SMR 22 and the Lambwave element 14 can include the same piezoelectric material, such asaluminum nitride (AlN). A piezoelectric layer 15′ of the acoustic wavedevice 20 can include a first portion that serves as a piezoelectriclayer for the Lamb wave element 14 and a second portion that serves as apiezoelectric layer for the SMR 22. The piezoelectric layer 15′ can havea different shape than the piezoelectric layer 15 in the acoustic wavedevice 10 of FIG. 1A.

The SMR 22 includes an acoustic mirror located between the substrate 19and the electrode 13B. The illustrated acoustic mirror includes Braggreflectors 24. As illustrated, the Bragg reflectors 24 includealternating low impedance and high impedance layers 25 and 26,respectively. As an example, the Bragg reflectors 24 can include silicondioxide (SiO₂) layers and tungsten (W) layers. As another example, theBragg reflectors 24 can include silicon dioxide layers and molybdenum(Mo) layers. Any other suitable Bragg reflectors can alternatively oradditionally be included in the SMR 22. The Lamb wave element 14 of FIG.2 includes its own an air cavity 18B. The Lamb wave element 14 and theSMR 22 can be disposed on a common substrate 19. The substrate 19 can bea semiconductor substrate. For example, the substrate 19 can be asilicon substrate. The substrate 19 can be any other suitable substratedisclosed herein.

FIG. 3A is a diagram of cross section of an acoustic wave device 30 thatincludes a Lamb wave element 14 and a surface acoustic wave (SAW)resonator 32 according to an embodiment. In the acoustic wave device 30,the SAW resonator 32 and the Lamb wave element 14 are implemented on acommon substrate 19. The SAW resonator 32 can be included an acousticwave filter and the Lamb wave element can be included in a loop circuit.The SAW resonator 32 can include any suitable piezoelectric layer, suchas an aluminum nitride layer, a lithium niobate layer, a lithiumtantalate layer, or any suitable combination thereof. The SAW resonator32 and the Lamb wave element 14 can include the same piezoelectricmaterial, such as aluminum nitride, lithium niobate or lithiumtantalate. A piezoelectric layer 15″ of the acoustic wave device 30 caninclude a first portion that serves as a piezoelectric layer for theLamb wave element 14 and a second portion that serves as a piezoelectriclayer for the SAW resonator 32. The SAW resonator 32 includes an IDTelectrode 34 on the piezoelectric layer 15′. The piezoelectric layer 15″can have a different shape than the piezoelectric layer 15 in theacoustic wave device 10 of FIG. 1A. The Lamb wave element 14 and the SAW32 can be disposed on a common substrate 19. The substrate 19 can be asemiconductor substrate, such as a silicon substrate.

FIG. 3B is a diagram of cross section of an acoustic wave device 30′that includes a Lamb wave element 14 and an SAW resonator 32′ accordingto an embodiment. The acoustic wave device 30′ is like the acoustic wavedevice 30 of FIG. 3A except that the respective piezoelectric layers 15″and 35 of the Lamb wave element 14 and the SAW resonator 32′ includedifferent piezoelectric material. For example, the SAW resonator 32′ caninclude a lithium niobate piezoelectric layer 35 and the Lamb waveelement 14 can include a lithium niobate piezoelectric layer 15″. Asanother example, the SAW resonator 32′ can include a lithium tantalatepiezoelectric layer 35 and the Lamb wave element 14 can include alithium tantalate piezoelectric layer 15″.

Although the acoustic wave devices 30 and 30′ are illustrated with aLamb wave element that includes a cavity 18B over the substrate 19,similar acoustic wave devices can be implemented with a cavity in thesubstrate (e.g., like the cavity 18B′ of FIG. 1B).

FIG. 4A is a diagram of cross section of an acoustic wave device 40 thatincludes a Lamb wave element 14 and a Lamb wave resonator 42 accordingto an embodiment. In the acoustic wave device 40, the Lamb waveresonator 42 and the Lamb wave element 14 are implemented on a commonsubstrate 19. The Lamb wave resonator 42 can be included in an acousticwave filter and the Lamb wave element 14 can be included in a loopcircuit. The Lamb wave resonator 42 can have the same or similarstructure as the Lamb wave element 14. In some instances, the Lamb waveelement 14 can include two sets of IDTs and the Lamb wave resonator 42can include a single set of IDTs. The Lamb wave element 14 and The Lambwave resonator 42 can share a piezoelectric layer 15. As shown in FIG.4A, the Lamb wave element 14 and The Lamb wave resonator 42 can share anair cavity 18. In certain applications, sharing an air cavity 18 canreduce the size of an acoustic wave device relative to implementingseparate air cavities.

FIG. 4B is a diagram of cross section of an acoustic wave device 40′that includes a Lamb wave element 14 and a Lamb wave resonator 42according to an embodiment. The acoustic wave device 40′ is like theacoustic wave device 40 of FIG. 40A except that separate air cavities18A and 18B are included in the acoustic wave device 40′ for the Lambwave resonator 42 and the Lamb wave element 14, respectively. In theacoustic wave device 40′, a first air cavity 18A is provided for theLamb wave resonator 42 and a second air cavity 18B is provided for theLamb wave element 14. In certain instances, having separate air cavitiescan be beneficial for maintaining the mechanical integrity of theacoustic wave device 40′ and/or reducing cross talk between the Lambwave resonator 42 and the Lamb wave element 14.

FIG. 5A is a diagram of cross section of an acoustic wave device 50 thatincludes a Lamb wave element 14 and a solidly mounted Lamb waveresonator 52 according to an embodiment. In the acoustic wave device 50,the solidly mounted Lamb wave resonator 52 and the Lamb wave element 14are implemented on a common substrate 19. The solidly mounted Lamb waveresonator 52 can be included in an acoustic wave filter and the Lambwave element 14 can be included in a loop circuit. The solidly mountedLamb wave resonator 52 and the Lamb wave element 14 can include the samepiezoelectric material, such as aluminum nitride. A piezoelectric layer15′ of the acoustic wave device 50 can include a first portion thatserves as a piezoelectric layer for the Lamb wave element 14 and asecond portion that serves as a piezoelectric layer for the solidlymounted Lamb wave resonator 52.

The solidly mounted Lamb wave resonator 52 includes features of a SAWresonator and an SMR. The solidly mounted Lamb wave resonator 52includes a lower electrode 53, a piezoelectric layer, an IDT electrode54 on the piezoelectric layer, and an acoustic mirror located betweenthe substrate 19 and the electrode 53. The illustrated acoustic mirrorincludes Bragg reflectors 56. As illustrated, the Bragg reflectors 56include alternating low impedance and high impedance layers 57 and 58,respectively. As an example, the Bragg reflectors 56 can include silicondioxide layers and tungsten layers. Any other suitable Bragg reflectorscan alternatively or additionally be included in the solidly mountedLamb wave resonator 52. The solidly mounted Lamb wave resonator 52 caninclude an aluminum nitride piezoelectric layer, for example.

FIG. 5B is a diagram of cross section of an acoustic wave device 50′that includes a Lamb wave element 14 and solidly mounted Lamb waveresonator 52 according to an embodiment. The acoustic wave device 50′ islike the acoustic wave device 50 of FIG. 5A except that the respectivepiezoelectric layers 15′ and 59 of the Lamb wave element 14 and thesolidly mounted Lamb wave resonator 52 include different piezoelectricmaterial.

FIG. 5C is a diagram of cross section of an acoustic wave device 50″that includes a Lamb wave element 14 and solidly mounted Lamb waveresonator 52 according to an embodiment. The acoustic wave device 50″ islike the acoustic wave device 50 of FIG. 5A except that an air cavity18B′ is implemented in the substrate 19 instead of over the substrate 19of FIG. 5A. The air cavity 18B′ can be implemented for the acoustic wavedevice 50″ by etching a portion of the substrate 19′.

FIG. 5D is a diagram of cross section of an acoustic wave device 50′″that includes a Lamb wave element 14 and solidly mounted Lamb waveresonator 52 according to an embodiment. The acoustic wave device 50′ islike the acoustic wave device 50″ of FIG. 5C except that the respectivepiezoelectric layers 15′ and 59 of the Lamb wave element 14 and thesolidly mounted Lamb wave resonator 52 include different piezoelectricmaterial.

A loop circuit can include a solidly mounted Lamb wave element. Forexample, such a Lamb wave element and a resonator of an acoustic wavefilter coupled to the loop circuit can be implemented in accordance withany suitable principles and advantages of the acoustic wave devices ofFIGS. 6 to 10. The acoustic wave devices of FIGS. 6 to 10 can also beimplemented in other applications. Any suitable combination of featuresof acoustic wave devices of FIGS. 6 to 10 can be implemented togetherwith each other.

FIG. 6 is a diagram of cross section of an acoustic wave device 60 thatincludes a solidly mounted Lamb wave element 64 and an FBAR 12′according to an embodiment. The FBAR 12′ and the solidly mounted Lambwave element 64 are implemented on a common substrate 19. The FBAR 12′can be included in an acoustic wave filter and the solidly mounted Lambwave element 64 can be included in a loop circuit. The solidly mountedLamb wave element 64 can be a solidly mounted Lamb wave resonator incertain instances. The solidly mounted Lamb wave element 64 can be adelay line in some instances. A Lamb wave delay line can include twosets of interdigital transducers.

The Lamb wave element 64 includes feature of a SAW resonator and an SMR.As illustrated, the Lamb wave element 64 includes a piezoelectric layer15′″, an IDT electrode 16 on the piezoelectric layer 15′″, and anelectrode 17. The piezoelectric layer 15′″ can be an aluminum nitridelayer. In other instances, the piezoelectric layer 15′″ can be any othersuitable piezoelectric layer. The frequency of the Lamb wave element 64can be based on the geometry of the IDT electrode 16. The electrode 17can be grounded in certain instances. In some other instances, theelectrode 17 can be floating. The Lamb wave element 64 includes anacoustic mirror located between the substrate 19 and the electrode 17.The illustrated acoustic mirror includes Bragg reflectors 65. Asillustrated, the Bragg reflectors 65 include alternating low impedanceand high impedance layers 66 and 67, respectively. As an example, theBragg reflectors 65 can include silicon dioxide layers and tungstenlayers. As another example, the Bragg reflectors 65 can include silicondioxide layers and molybdenum layers. Any other suitable Braggreflectors can alternatively or additionally be included in the Lambwave element 64.

In the acoustic wave device 60, the Lamb wave element 64 and the FBAR12′ can share a piezoelectric layer 15′″. In some other embodiments, theLamb wave element 64 and the FBAR 12′ can include piezoelectric layersof different material. The piezoelectric layer 15′″ can have a differentshape than piezoelectric layers in other embodiments that have differentresonator combinations. The Lamb wave element 64 and the FBAR 12′ can bedisposed on a common substrate 19. The substrate 19 can be asemiconductor substrate. For example, the substrate 19 can be asemiconductor substrate. The substrate 19 can be any other suitablesubstrate, such as a quartz substrate, a sapphire substrate, or a spinelsubstrate.

FIG. 7 is a diagram of cross section of an acoustic wave device 70 thatincludes a solidly mounted Lamb wave element 64 and an SMR 22 accordingto an embodiment. In the acoustic wave device 70, the SMR 22 and theLamb wave element 64 are implemented on a common substrate 19. The SMR22 can be included in an acoustic wave filter and the Lamb wave element64 can be included in a loop circuit. The solidly mounted Lamb waveelement 64 is structurally similar to the SMR 22, except that thesolidly mounted Lamb wave element 64 includes an IDT electrode 16 andthe SMR 22 includes an electrode 13A having a different shape than theIDT electrode 16 over the piezoelectric layer 15″″. The Bragg reflectors65 for the solidly mounted Lamb wave element 64 and the Bragg reflectors24 for the SMR 22 can be separated by material of the substrate 19. Forinstance, semiconductor material of a semiconductor substrate 19 canseparate Bragg reflectors 24 from Bragg reflectors 65. The Braggreflectors 65 and 24 can include the same materials in certainapplications. The Bragg reflectors 65 and 24 can include differentmaterials in certain applications. In some applications, Braggreflectors can form a common acoustic mirror below the Lamb wave element64 and the SMR 22. The piezoelectric layers 15′″ and 68 of the solidlymounted Lamb wave element 64 and the SMR 22, respectively, can includethe same piezoelectric material in certain applications. Thepiezoelectric layers 15′″ and 68 of the solidly mounted Lamb waveelement 64 and the SMR 22, respectively, can include differentpiezoelectric material in various applications.

FIG. 8 is a diagram of cross section of an acoustic wave device 80 thatincludes a solidly mounted Lamb wave element 64 and a SAW resonator 32according to an embodiment. The solidly mounted Lamb wave element 64 andthe SAW resonator 32 can be on a common substrate 19. The SAW resonator32 can be included in an acoustic wave filter and the Lamb wave element64 can be included in a loop circuit. The piezoelectric layers 15″″ and35 of the solidly mounted Lamb wave element 64 and the SAW resonator 32,respectively, can include the same piezoelectric material in certainapplications. The piezoelectric layers 15″″ and 35 of the solidlymounted Lamb wave element 64 and the SAW resonator 32, respectively, caninclude different piezoelectric material in various applications.

FIG. 9 is a diagram of cross section of an acoustic wave device 90 thatincludes a solidly mounted Lamb wave element 64 of and a Lamb waveresonator 42′ according to an embodiment. The Lamb wave resonator 42′ isa free-standing Lamb wave resonator. The solidly mounted Lamb waveelement 64 and the Lamb wave resonator 42′ can include the samepiezoelectric material, such as aluminum nitride, lithium niobate, orlithium tantalate. In some other applications, the solidly mounted Lambwave element 64 and the Lamb wave resonator 42′ can includepiezoelectric layers of different material. The solidly mounted Lambwave element 64 and the Lamb wave resonator 42′ can be disposed on acommon substrate 19. The Lamb wave resonator 42′ can be included in anacoustic wave filter and the Lamb wave element 64 can be included in aloop circuit.

FIG. 10 is a diagram of cross section of an acoustic wave device 100that includes a solidly mounted Lamb wave element 64 and a solidlymounted Lamb wave resonator 52 according to an embodiment. These solidlymounted Lamb wave elements can be structurally similar or the same. Inthe acoustic wave device 100, the solidly mounted Lamb wave resonator 52and the Lamb wave element 64 are implemented on a common substrate 19.The solidly mounted Lamb wave resonator 52 can be included in anacoustic wave filter and the Lamb wave element 64 can be included in aloop circuit. Semiconductor material of the semiconductor substrate 19can separate Bragg reflectors of these solidly mounted Lamb waveelements. The Bragg reflectors 65 and 56 can include the same materialsin certain applications. The Bragg reflectors 65 and 56 can includedifferent materials in certain applications. In some applications, Braggreflectors can form a common acoustic mirror below the Lamb wave element64 and the solidly mounted Lamb wave resonator 52. The piezoelectriclayers 15′″ and 59 of the solidly mounted Lamb wave element 64 and thesolidly mounted Lamb wave resonator 52, respectively, can include thesame piezoelectric material in certain applications. The piezoelectriclayers 15′″ and 68 of the solidly mounted Lamb wave element 64 and thesolidly mounted Lamb wave resonator 52, respectively, can includedifferent piezoelectric material in various applications.

Lamb wave elements can include an IDT electrode on a piezoelectric layerand reflective gratings disposed on the piezoelectric layer on opposingsides of the IDT electrode. The reflective gratings can reflect acousticwaves induced by the IDT electrode to form a resonant cavity. Thereflective gratings can include a periodic pattern of metal on apiezoelectric layer. FIGS. 11A to 11F are diagrams of cross sections ofLamb wave elements with gratings. A Lamb wave element in a loop circuitcan be implemented with any suitable principles and advantages of any ofthe Lamb wave elements of FIGS. 11A to 11F. A Lamb wave resonator in afilter can be implemented with any suitable principles and advantages ofany of the Lamb wave elements of FIGS. 11A to 11F. Although the Lambwave elements of FIGS. 11A to 11F are free-standing resonators, anysuitable principles and advantages of these Lamb wave resonators can beapplied to any other suitable Lamb wave elements.

FIG. 11A illustrates a Lamb wave element 110 that includes an IDTelectrode 112, gratings 113 and 114, a piezoelectric layer 115, and anelectrode 116. The IDT electrode 112 is on the piezoelectric layer 115.In the illustrated cross section, alternate ground and signal metals areincluded in the IDT electrodes. Gratings 113 and 115 are on thepiezoelectric layer 115 and disposed on opposing sides of the IDTelectrodes 112. The illustrated gratings 113 and 115 are shown as beingconnected to ground. Alternatively, one or more of the gratings can besignaled and/or floating. The electrode 116 and the IDT electrode 112are on opposite sides of the piezoelectric layer 115. The piezoelectriclayer 115 can be aluminum nitride, for example. The electrode 116 can begrounded.

FIG. 11B illustrates a Lamb wave element 110′. The Lamb wave element110′ is like the Lamb wave element 110 of FIG. 11A except that the Lambwave element 110′ includes a floating electrode 116′.

FIG. 11C illustrates a Lamb wave element 110″ without an electrode on aside of the piezoelectric layer 115 that opposes the IDT electrode 112.The Lamb wave element 110″ is otherwise like the Lamb wave element 110of FIG. 11A.

FIG. 11D illustrates a Lamb wave element 110′″ that includes an IDTelectrode 117 and gratings 118 and 119 on a second side of thepiezoelectric layer 115 that is opposite to a first side on which theIDT electrode 112 and gratings 113 and 114 are disposed. The signal andground electrodes are offset relative to each other for the IDTelectrodes 112 and 117.

FIG. 11E illustrates a Lamb wave element 110″″ that includes an IDTelectrode 117′ and gratings 118 and 119 on a second side of thepiezoelectric layer 115 that is opposite to a first side on which theIDT electrode 112 and gratings 113 and 114 are disposed. The signal andground electrodes are aligned with each other for the IDT electrodes 112and 117′.

FIG. 11F illustrates a Lamb wave element 110′″″ that includes an IDTelectrode 117″ and gratings 118 and 119 on a second side of thepiezoelectric layer 115 that is opposite to a first side on which theIDT electrode 112′ and gratings 113 and 114 are disposed. In theillustrated cross section, the IDT 112′ includes only signal electrodesand the IDT electrode 117″ includes only ground electrodes.

Lamb wave elements can include an IDT electrode with free edges.Suspended free edges of a piezoelectric layer can provide acoustic wavereflection to form a resonant cavity. FIGS. 12A to 12F are diagrams ofcross sections of Lamb wave elements with free edges. A Lamb waveelement in a loop circuit can be implemented with any suitableprinciples and advantages of any of the Lamb wave elements of FIGS. 12Ato 12F. A Lamb wave resonator in a filter can be implemented with anysuitable principles and advantages of any of the Lamb wave elements ofFIGS. 12A to 12F. Although the Lamb wave elements of FIGS. 12A to 12Fare free-standing elements, any suitable principles and advantages ofthese Lamb wave elements can be applied to other Lamb wave elements.

FIG. 12A illustrates a Lamb wave element 120 that includes IDT electrode112, piezoelectric layer 115, and an electrode 116. The IDT electrode112 is on the piezoelectric layer 115. In the illustrated cross section,alternate ground and signal electrodes are included in the IDTelectrodes. The piezoelectric layer 115 has free edges on opposing sidesof the IDT electrode 112. The electrode 116 and the IDT electrode 112are on opposite sides of the piezoelectric layer 115. The piezoelectriclayer 115 can be aluminum nitride, for example. The electrode 116 can begrounded.

FIG. 12B illustrates a Lamb wave element 120′. The Lamb wave element120′ is like the Lamb wave element 120 of FIG. 12A except that the Lambwave element 120′ includes a floating electrode 116′.

FIG. 12C illustrates a Lamb wave element 120″ without an electrode on aside of the piezoelectric layer 115 that opposes the IDT electrode 112.The Lamb wave element 120″ is otherwise like the Lamb wave element 120of FIG. 12A.

FIG. 12D illustrates a Lamb wave element 120′″ that includes an IDTelectrode 117 on a second side of the piezoelectric layer 115 that isopposite to a first side on which the IDT electrode 112 is disposed. Thesignal and ground electrodes are offset relative to each other for theIDT electrodes 112 and 117.

FIG. 12E illustrates a Lamb wave element 120″″ that includes an IDTelectrode 117′ on a second side of the piezoelectric layer 115 that isopposite to a first side on which the IDT electrode 112 is disposed. Thesignal and ground electrodes are aligned with each other for the IDTelectrodes 112 and 117′.

FIG. 12F illustrates a Lamb wave element 120′″″ that includes an IDTelectrode 117″ on a second side of the piezoelectric layer 115 that isopposite to a first side on which the IDT electrode 112′ is disposed. Inthe illustrated cross section, the IDT electrode 112′ includes onlysignal electrodes and the IDT electrode 117″ includes only groundelectrodes.

The Lamb wave loop circuits discussed herein can be coupled to anacoustic wave filter. For instance, a Lamb wave element can be coupledto an acoustic wave filter of a duplexer or other multiplexer (e.g., aquadplexer, hexaplexer, octoplexer, etc.). FIGS. 13, 15, 17, and 19 areschematic diagrams that illustrate example duplexers that include a Lambwave loop circuit coupled to an acoustic wave filter. Any suitableprinciples and advantages discussed with reference to and/or illustratedin FIGS. 1A to 12F can be applied to any of the example duplexers ofFIGS. 13, 15, 17, and 19. Any suitable principles and advantages of theembodiments of FIGS. 13, 15, 17, and 19 can be implemented together witheach other.

FIG. 13 is a schematic diagram of a duplexer 130 with a loop circuit 133for a transmit filter 132. The duplexer 130 includes a transmit filter132, a receive filter 134, and a loop circuit 133. The transmit filter132 and the receive filter 134 are coupled together at a common node,which is an antenna node in FIG. 13. An antenna 135 is coupled to thecommon node of the duplexer 130. A shunt inductor L1 can be coupledbetween the antenna 135 and ground.

The transmit filter 132 can filter an RF signal received at the transmitport TX for transmission via the antenna 135. A series inductor L2 canbe coupled between the transmit port TX and acoustic wave resonators ofthe transmit filter 132. The transmit filter 132 is an acoustic wavefilter that includes acoustic wave resonators arranged as a ladderfilter. The transmit filter 132 includes series resonators T01, T03,T05, T07, T09 and shunt resonators T02, T04, T06, T08. The transmitfilter 132 can include any suitable number of series resonators and anysuitable number of shunt resonators. The acoustic wave resonators of thetransmit filter 132 can include BAW resonators, such as FBARs and/orSMRs. In some instances, the acoustic wave resonators of the transmitfilter 132 can include SAW resonators or Lamb wave resonators. Incertain applications, the resonators of the transmit filter 132 caninclude two or more types of resonators (e.g., one or more SAWresonators and one or more BAW resonators).

A loop circuit 133 is coupled to the transmit filter 132. The loopcircuit 133 can be coupled to an input resonator T01 and an outputresonator T09 of the transmit filter. In some other instances, the loopcircuit 133 can be coupled to a different node of the ladder circuitthan illustrated. The loop circuit 133 can apply a signal havingapproximately the same amplitude and an opposite phase to a signalcomponent to be canceled. The loop circuit 133 includes Lamb waveelements 136 and 137 coupled to the transmit filter 132 by capacitorsCAP02 and CAP01, respectively. The Lamb wave elements 136 and 137 cantogether correspond to any suitable Lamb wave element disclosed herein.For example, the Lamb wave elements 136 and 137 can together correspondto the Lamb wave element 14 of FIG. 1A, in which each Lamb wave element136 and 137 corresponds to a different IDT electrode of the Lamb waveelement 14. In this example, the transmit filter 132 can include an FBARimplemented on the same substrate of a die as the Lamb wave element 14.The capacitors CAP01 and CAP02 are example attenuation elements that cancoupled the transmit filter 132 to the loop circuit 133. In variousapplications, an attenuation element can include a resistor, aninductor, a capacitor, or any suitable combination thereof. Any suitableprinciples and advantages of the Lamb wave elements of a loop circuitdiscussed herein can be implemented in the loop circuit 133. The loopcircuit 133 can be implemented in accordance with any suitableprinciples and advantages described in U.S. Pat. Nos. 9,246,533 and/or9,520,857, the disclosures of these patents are hereby incorporated byreference in their entireties herein.

The receive filter 134 can filter a received RF signal received by theantenna 135 and provide a filtered RF signal to a receive port RX. Thereceive filter 134 is an acoustic wave filter that includes acousticwave resonators arranged as a ladder filter. The receive filter 134includes series resonators R01, R03, R05, R07, R09 and shunt resonatorsR02, R04, R06, R08. The receive filter 134 can include any suitablenumber of series resonators and any suitable number of shunt resonators.The acoustic wave resonators of the receive filter 134 can include BAWresonators, such as FBARs and/or SMRs. In some instances, the acousticwave resonators of the receive filter 134 can include SAW resonators orLamb wave resonators. In certain applications, the resonators of thereceive filter 134 can include two or more types of resonators (e.g.,one or more SAW resonators and one or more BAW resonators). A seriesinductor L3 can be coupled between the acoustic wave resonators of thereceive filter 134 and the receive port RX.

FIG. 14 is a graph comparing isolation for the duplexer 130 of FIG. 13to a corresponding duplexer without a loop circuit. The acoustic waveproperties of the lowest-order symmetric (S₀) Lamb wave mode for a Lambwave resonator with an aluminum nitride piezoelectric layer were used tostudy the loop circuits for BAW filters. The Lamb wave S₀ mode for sucha resonator in the simulations was assumed to have a velocity of ˜9000m/s and a K² of ˜2%. A Band 7 BAW duplexer was used in the simulations.The graph in FIG. 14 indicates that the loop circuit 133 improvesreceive isolation. The improvement can be about 5 decibels (dB) incertain instances as indicated by FIG. 14.

FIG. 15 is a schematic diagram of a duplexer 150 with a loop circuit fora receive filter 134. The duplexer 150 is like the duplexer 130 of FIG.13, except that the duplexer 150 includes a loop circuit 153 for thereceive filter 134. A loop circuit 153 is coupled to the receive filter134. The loop circuit 153 can be coupled to an input resonator R09 andan output resonator R01 of the receive filter 134. In some otherinstances, the loop circuit 153 can be coupled to a different node ofthe ladder circuit of the receive filter 134 than illustrated. The loopcircuit 153 includes Lamb wave elements 156 and 157 coupled to thereceive filter 134 by capacitors CAP04 and CAP03, respectively. Anysuitable principles and advantages of the Lamb wave elements of a loopcircuit discussed herein can be implemented in the loop circuit 153. Forexample, the Lamb wave elements 156 and 157 can together correspond tothe Lamb wave element 14 of FIG. 14A.

FIG. 16A is a graph comparing isolation for the duplexer 150 of FIG. 15to a corresponding duplexer without a loop circuit. The same simulationassumptions were used to generate the graphs of FIG. 16A and FIG. 16B asfor generating the graph of FIG. 14. The graph of FIG. 16A indicatesthat the loop circuit 153 improves transmit isolation.

FIG. 16B is a graph comparing receive band rejection for the duplexer150 of FIG. 15 to a corresponding duplexer without a loop circuit. Thisgraph illustrates that the loop circuit 153 can suppress rejection at alower frequency range for the receive band.

FIG. 17 is a schematic diagram of a duplexer 170 with a first loopcircuit 133 for a transmit filter 132 and a second loop circuit 153 fora receive filter 134. FIG. 17 illustrates that separate loop circuitscan be implemented for a transmit filter and a receive filter. A loopcircuit can be implemented for an acoustic wave filter to bring theparameter of the acoustic wave filter within a specification. Forexample, a loop circuit can be implemented to bring isolation of anacoustic wave filter to be less than −60 dB to meet a specification forisolation if the acoustic wave filter would not otherwise meet thespecification for isolation.

FIG. 18 is a graph comparing isolation for the duplexer 170 of FIG. 17to a corresponding duplexer without loop circuits. This graph indicatesthat the loop circuits 133 and 153 of the duplexer 170 improve bothtransmit and receive isolation.

FIG. 19 is a schematic diagram of a duplexer 190 with a loop circuit193. The duplexer 190 is like the duplexer 130 of FIG. 13, except thatthe duplexer 190 includes a loop circuit 193 that is coupled across thetransmit filter 132 and the receive filter 134. The loop circuit 193 iscoupled to the receive port RX and the transmit port TX. In some otherinstances, the loop circuit 193 can be coupled to a different node ofthe ladder circuit of the receive filter 134 and/or a different node ofthe transmit filter 132 than illustrated. The loop circuit 193 includesLamb wave elements 196 and 197. The Lamb wave element 196 is coupled tothe transmit filter by capacitor CAP01. The Lamb wave element 197 iscoupled to the receive filter 134 by capacitor C02. Any other suitableattenuation element, such as a resistor or an inductor, can beimplemented in place of or in addition to the capacitor C01 and/or thecapacitor C02. Any suitable principles and advantages of the Lamb waveelements of a loop circuit discussed herein can be implemented in theloop circuit 193. For example, the Lamb wave elements 196 and 197 cantogether correspond to the Lamb wave element 14 of FIG. 14A.

Acoustic wave devices disclosed herein can be implemented in acousticwave filters. Such acoustic wave filters can be band pass filtersarranged to filter radio frequency signals including radio frequencysignals at up to and including millimeter wave frequencies. In certainapplications, an acoustic wave filter assembly can include a firstfilter that includes a Lamb wave resonator and a second filter thatincludes a different type of resonator, such as an FBAR. The firstfilter and the second filter can be included on a single die. Aschematic diagram of an example acoustic wave filter assembly will bediscussed with reference to FIG. 20. Although an acoustic wave filterassembly with two filters will be described for illustrative purposes,any suitable principles and advantages can be applied to acoustic wavefilter assemblies with more than two filters.

FIG. 20 is a schematic diagram of an acoustic wave filter assembly 200that includes a first filter 202 with a Lamb wave resonator and a secondfilter 204 with a different type of acoustic wave resonator, in whichthe Lamb wave resonator and the different type of resonator areimplemented on the same substrate according to an embodiment. Theacoustic wave filter assembly 200 can include any of the acoustic wavedevices of FIGS. 1A to 10.

The first filter 202 includes Lamb wave resonators L01, L02, L03, L04,L05, L06, L07, L08, and L09 arranged as a ladder filter between an RFport RF1 and an antenna port ANT. The RF port RF1 can be a transmit portor a receive port. The first filter 202 is a band pass filter having afirst pass band and arranged to filter a first RF signal.

The second filter 204 includes acoustic wave resonators B01, B02, B03,B04, B05, B06, B07, B08, and B09 arranged as a ladder filter between anRF port RF2 and an antenna port ANT. The RF port RF2 can be a transmitport or a receive port. The second filter 204 is a band pass filterhaving a second pass band and arranged to filter a second RF signal. Theacoustic wave resonators B01 to B09 of the second filter 204 are adifferent type of acoustic wave resonators than the Lamb wave resonatorsL01 to L09 of the first filter 202. For example, the acoustic waveresonators B01 to B09 of the second filter 204 can be BAW resonators,such as FBARs.

Some or all of the Lamb wave resonators L01 to L09 of the first filter202 can be implemented on the same substrate of die as some or all ofthe acoustic wave resonators B01 to B09 of the second filter 204. Incertain instances, one or more resonators of the Lamb wave resonatorsL01 to L09 include a piezoelectric layer that includes the same material(e.g., aluminum nitride) as the piezoelectric layer of one or more ofthe acoustic wave resonators B01 to B09. In some applications, amultiplexer (e.g., a duplexer) can include the first filter 202 and thesecond filter 204 coupled together at a common node (e.g., the antennanode ANT).

Acoustic wave devices disclosed herein can be implemented in an acousticwave filter that includes a Lamb wave resonator and a different type ofacoustic wave resonator. Such an acoustic wave filter can include anysuitable acoustic wave device disclosed herein. The acoustic wave filtercan be band pass filters arranged to filter radio frequency signals. TheLamb wave resonator and the different type of acoustic wave resonatorcan be implemented on the same substrate of a die. The substrate can bea silicon substrate, for example. In some instances, the different typeof acoustic wave resonator can be an FBAR. The different type ofacoustic wave resonator and the Lamb wave resonator can includerespective piezoelectric layer of the same piezoelectric material (forexample, aluminum nitride) in certain applications. Example acousticwave filters with a Lamb wave resonator and another type of acousticwave resonator will be discussed with reference to FIGS. 21A to 21F.These example acoustic wave filters can achieve desirable performanceand/or loading characteristics for certain applications. Any suitableprinciples and advantages of these acoustic wave filters can beimplemented together with each other. Moreover, any of the exampleacoustic wave filters of FIGS. 21A to 21F can include an acoustic wavedevice in accordance with any suitable principles and advantages ofFIGS. 1A to 10.

FIG. 21A is a schematic diagram of an acoustic wave filter 210 thatincludes series Lamb wave resonators and other shunt acoustic waveresonators according to an embodiment. The series Lamb wave resonatorsLS01, LS02, LS03, LS04, and LS05 and other shunt acoustic waveresonators BP01, BP02, BP03, BP04, and BP05 are arranged as a ladderfilter coupled between an RF port RF and an antenna port ANT. The RFport RF can be a transmit port of a transmit filter. The RF port can bea receive port of a receive filter. Any suitable number of seriesresonators and any suitable number of shunt resonators can be includedin the acoustic wave filter 210. The other shunt acoustic waveresonators BP01, BP02, BP03, BP04, and BP05 can be FBARs. In some otherinstances, the other shunt acoustic wave BP01, BP02, BP03, BP04, andBP05 can be SAW resonators or SMRs.

FIG. 21B is a schematic diagram of an acoustic wave filter 212 thatincludes shunt Lamb wave resonators and other series acoustic waveresonators according to an embodiment. The shunt Lamb wave resonatorsLP01, LP02, LP03, LP04, and LP05 and other series acoustic waveresonators BS01, B502, B503, B504, and B505 are arranged as a ladderfilter coupled between an RF port RF and an antenna port ANT. The RFport RF can be a transmit port of a transmit filter. The RF port can bea receive port of a receive filter. Any suitable number of seriesresonators and any suitable number of shunt resonators can be includedin the acoustic wave filter 212. The other series acoustic waveresonators BS01, B502, B503, B504, and B505 can be FBARs. In some otherinstances, the other shunt acoustic wave BS01, B502, B503, B504, andB505 can be SAW resonators or SMRs.

FIG. 21C is a schematic diagram of an acoustic wave filter 214 thatincludes a series Lamb wave resonator LS and other acoustic waveresonators B01 to B08 coupled to an antenna port ANT via the series Lambwave resonator LS according to an embodiment. The other acoustic waveresonators B01 to B08 can be SAW resonators or BAW resonators.

FIG. 21D is a schematic diagram of an acoustic wave filter 216 thatincludes a series Lamb wave resonator LS and other acoustic waveresonators B02 to B09 coupled to a radio frequency port RF via theseries Lamb wave resonator LS according to an embodiment. The otheracoustic wave resonators B02 to B09 can be SAW resonators or BAWresonators.

FIG. 21E is a schematic diagram of an acoustic wave filter 218 thatincludes a series Lamb wave resonator LS and other acoustic waveresonators B01 to B04 and B06 to B09 according to an embodiment. In theacoustic wave filter 218, a first other series resonator B01 is coupledbetween the series Lamb wave resonator LS and the RF port RF. A secondother series resonator B09 is coupled between the series Lamb waveresonator LS and the antenna port ANT in the acoustic wave filter 218.The other acoustic wave resonators B01 to B04 and B06 to B09 can be SAWresonators or BAW resonators.

FIG. 21F is a schematic diagram of an acoustic wave filter 219 thatincludes a shunt Lamb wave resonator LP and other acoustic waveresonators B01 to B05 and B07 to B09 according to an embodiment.

In the acoustic wave filter 219, a first other series resonator B01 iscoupled between the shunt Lamb wave resonator LP and the RF port RF. Asecond other series resonator B09 is coupled between the shunt Lamb waveresonator LP and the antenna port ANT in the acoustic wave filter 219.The other acoustic wave resonators B01 to B05 and B07 to B09 can be SAWresonators or BAW resonators.

The acoustic wave devices and/or loop circuits discussed herein can beimplemented in a variety of packaged modules. Some example packagedmodules will now be discussed in which any suitable principles andadvantages of the Lamb wave loop circuits discussed herein can beimplemented. FIGS. 22A, 22B, 22C, and 22D are schematic block diagramsof illustrative packaged modules according to certain embodiments.

FIG. 22A is a schematic block diagram of a module 220 that includes aduplexer 222 with a Lamb wave loop circuit and an antenna switch 223.The module 220 can include a package that encloses the illustratedelements. The duplexer 222 with a Lamb wave loop circuit and the antennaswitch 223 can be disposed on a common packaging substrate. Thepackaging substrate can be a laminate substrate, for example. Theduplexer 222 can include a Lamb wave loop circuit in accordance with anysuitable principles and advantages discussed herein. The antenna switch223 can be a multi-throw radio frequency switch. The antenna switch 223can selectively electrically couple a common node of the duplexer 222 toan antenna port of the module 220.

FIG. 22B is a schematic block diagram of a module 220′ that includes afirst filter 222A with a Lamb wave loop circuit, a second filter 222Bwith a Lamb wave loop circuit, and an antenna switch 223′. The module220′ illustrates that two different filters with Lamb wave loop circuitscan be included in a module. The first filter 222A with a Lamb wave loopcircuit can be implemented on a different die than the second filter222B with a Lamb wave loop circuit. The antenna switch 223′ canselectively electrically couple a port of the first filter 222A and/orthe second filter 222B to an antenna port of the module 220′.

FIG. 22C is a schematic block diagram of a module 224 that includes apower amplifier 225, a switch 226, and a duplexer 222 with a Lamb waveloop circuit. The power amplifier 225 can amplify a radio frequencysignal. The switch 226 can selectively electrically couple an output ofthe power amplifier 225 to a transmit port of the duplexer 222. Theduplexer 222 can include a Lamb wave loop circuit in accordance with anysuitable principles and advantages discussed herein.

FIG. 22D is a schematic block diagram of a module 227 that includespower amplifier 225, a switch 226, a duplexer 222 with a Lamb wave loopcircuit, and an antenna switch 223. The module 227 is similar to themodule 224 of FIG. 22C, except the module 227 additionally includes theantenna switch 223.

The acoustic wave filters with a Lamb wave resonator and/or another typeof acoustic wave resonator disclosed herein can be implemented in avariety of packaged modules. Some example packaged modules will now bediscussed in which any suitable principles and advantages of theacoustic wave filters with a Lamb wave resonator and a different type ofacoustic wave resonator discussed herein can be implemented. FIGS. 23A,23B, and 23C are schematic block diagrams of illustrative packagedmodules according to certain embodiments.

FIG. 23A is a schematic block diagram of a module 230 that includes oneor more filters 232 with a Lamb wave resonator and another type ofacoustic wave resonator. The one or more filters 232 can include anysuitable combination of features disclosed in association with FIGS. 20to 21F. The module 230 can include a package that encloses theillustrated elements. The one or more filters 232 with a Lamb waveresonator and another type of acoustic wave resonator and the antennaswitch 233 can be disposed on a common packaging substrate. Thepackaging substrate can be a laminate substrate, for example. Theantenna switch 233 can be a multi-throw radio frequency switch. Theantenna switch 233 can selectively electrically couple any suitablenumber of the one or more of the filters 232 to an antenna port of themodule 230.

FIG. 23B is a schematic block diagram of a module 234 that includes apower amplifier 235, a switch 236, and one or more filters 232 with aLamb wave resonator and another type of acoustic wave resonator. Thepower amplifier 235 can amplify a radio frequency signal. The switch 236can selectively electrically couple an output of the power amplifier 235to a transmit port of the duplexer 232. The one or more filters 232 witha Lamb wave resonator and another type of acoustic wave resonator can beimplemented in accordance with any suitable principles and advantagesdiscussed herein.

FIG. 23C is a schematic block diagram of a module 237 that includespower amplifier 235, a switch 236, one or more filters 232 with a Lambwave resonator and another type of acoustic wave resonator, and anantenna switch 233. The module 237 is similar to the module 234 of FIG.23B, except the module 237 additionally includes the antenna switch 233.

FIG. 24 is a schematic block diagram of a wireless communication device240 that includes filters 243 with one or more Lamb wave elements inaccordance with one or more embodiments. For example, the filters 243can include a duplexer with a Lamb wave loop circuit in accordance withany suitable principles and advantages disclosed herein. The filters 243can include a first filter with a Lamb wave resonator and a secondfilter with a different type of acoustic wave resonator, in which theLamb wave resonator and the different type of acoustic wave resonatorare implemented on a common substrate of a die. In certain instances,the filters 243 can include a filter that includes a Lamb wave resonatorand a different type of acoustic wave resonator.

The wireless communication device 240 can be any suitable wirelesscommunication device. For instance, a wireless communication device 240can be a mobile phone, such as a smart phone. As illustrated, thewireless communication device 240 includes an antenna 241, an RF frontend 242 that includes the filters 243, an RF transceiver 244, aprocessor 245, a memory 246, and a user interface. The antenna 241 cantransmit RF signals provided by the RF front end 242. The antenna 241can receive RF signals and provide the received RF signals to the RFfront end 242 for processing.

The RF front end 242 can include one or more power amplifiers, one ormore low noise amplifiers, RF switches, receive filters, transmitfilters, duplex filters, filters of a multiplexer, filters of adiplexers or other frequency multiplexing circuit, or any suitablecombination thereof. The filters 243 of the RF front end 242 can beimplemented in accordance with any suitable principles and advantagesdisclosed herein. The RF front end 242 can transmit and receive RFsignals associated with any suitable communication standards. Any of theacoustic wave devices and/or Lamb wave loop circuits discussed hereincan be implemented in the RF front end 242.

The RF transceiver 244 can provide RF signals to the RF front end 242for amplification and/or other processing. The RF transceiver 244 canalso process an RF signal provided by a low noise amplifier of the RFfront end 242. The RF transceiver 244 is in communication with theprocessor 245. The processor 245 can be a baseband processor. Theprocessor 245 can provide any suitable base band processing functionsfor the wireless communication device 240. The memory 246 can beaccessed by the processor 245. The memory 246 can store any suitabledata for the wireless communication device 240. The user interface 247can be any suitable user interface, such as a display with touch screencapabilities.

Any of the embodiments described above can be implemented in associationwith mobile devices such as cellular handsets. The principles andadvantages of the embodiments can be used for any systems or apparatus,such as any uplink wireless communication device, that could benefitfrom any of the embodiments described herein. The teachings herein areapplicable to a variety of systems. Although this disclosure includessome example embodiments, the teachings described herein can be appliedto a variety of structures. Any of the principles and advantagesdiscussed herein can be implemented in association with RF circuitsconfigured to process signals in a range from about 30 kHz to 300 GHz,such as in a range from about 450 MHz to 8.5 GHz.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as packaged radio frequency modules, uplinkwireless communication devices, wireless communication infrastructure,electronic test equipment, etc. Examples of the electronic devices caninclude, but are not limited to, a mobile phone such as a smart phone, awearable computing device such as a smart watch or an ear piece, atelephone, a television, a computer monitor, a computer, a modem, ahand-held computer, a laptop computer, a tablet computer, a microwave, arefrigerator, a vehicular electronics system such as an automotiveelectronics system, a stereo system, a digital music player, a radio, acamera such as a digital camera, a portable memory chip, a washer, adryer, a washer/dryer, a copier, a facsimile machine, a scanner, amulti-functional peripheral device, a wrist watch, a clock, etc.Further, the electronic devices can include unfinished products.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,”“include,” “including” and the like are to be construed in an inclusivesense, as opposed to an exclusive or exhaustive sense; that is to say,in the sense of “including, but not limited to.” The word “coupled”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Likewise, the word “connected”, as generally used herein,refers to two or more elements that may be either directly connected, orconnected by way of one or more intermediate elements. Additionally, thewords “herein,” “above,” “below,” and words of similar import, when usedin this application, shall refer to this application as a whole and notto any particular portions of this application. Where the contextpermits, words in the above Detailed Description using the singular orplural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel apparatus, methods, andsystems described herein may be embodied in a variety of other forms;furthermore, various omissions, substitutions and changes in the form ofthe methods and systems described herein may be made without departingfrom the spirit of the disclosure. For example, while blocks arepresented in a given arrangement, alternative embodiments may performsimilar functionalities with different components and/or circuittopologies, and some blocks may be deleted, moved, added, subdivided,combined, and/or modified. Each of these blocks may be implemented in avariety of different ways. Any suitable combination of the elements andacts of the various embodiments described above can be combined toprovide further embodiments. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of the disclosure.

What is claimed is:
 1. An acoustic wave device comprising: a band passfilter including a bulk acoustic wave resonator and additional bulkacoustic wave resonators, the band pass filter configured to filter aradio frequency signal; a Lamb wave element included in a loop circuit,the Lamb wave element coupled to the band pass filter by way of anattenuation element of the loop circuit, and the loop circuit configuredto generate an anti-phase signal to a target signal at a particularfrequency; the bulk acoustic wave resonator, the additional bulkacoustic wave resonators, and the Lamb wave element implemented on acommon substrate of a die; a second band pass filter including a surfaceacoustic wave resonator, the first band pass filter and the second bandpass filter being included in a multiplexer; and a second Lamb waveelement included in a second loop circuit, the second Lamb wave elementcoupled to the second band pass filter by way of a second attenuationelement of the second loop circuit, and the second loop circuit coupledin parallel with at least the surface acoustic wave resonator.
 2. Theacoustic wave device of claim 1 wherein the bulk acoustic wave resonatoris a film bulk acoustic resonator.
 3. The acoustic wave device of claim1 wherein the common substrate includes silicon.
 4. The acoustic wavedevice of claim 1 wherein the Lamb wave element includes a piezoelectriclayer that includes the same material as a piezoelectric layer of thebulk acoustic wave resonator.
 5. The acoustic wave device of claim 4wherein the material includes aluminum nitride.
 6. The acoustic wavedevice of claim 1 wherein the bulk acoustic wave resonator and the Lambwave element share a cavity.
 7. The acoustic wave device of claim 1wherein the bulk acoustic wave resonator and the Lamb wave element haveseparate cavities.
 8. The acoustic wave device of claim 1 wherein thebulk acoustic wave resonator is a solidly mounted resonator.
 9. Theacoustic wave device of claim 1 wherein the Lamb wave element includes aBragg reflector.
 10. The acoustic wave device of claim 1 wherein theLamb wave element includes an interdigital transducer electrode on apiezoelectric layer and gratings disposed on the piezoelectric layer onopposing sides of the interdigital transducer electrode.
 11. Theacoustic wave device of claim 1 wherein the Lamb wave element includesan interdigital transducer electrode on a piezoelectric layer, theinterdigital transducer electrode having free edges.
 12. The acousticwave device of claim 1 wherein the loop circuit is coupled to the bandpass filter at an input resonator and at an output resonator, the inputresonator being the bulk acoustic wave resonator, and the outputresonator being included in the additional bulk acoustic waveresonators.
 13. The acoustic wave device of claim 1 wherein theattenuation element is a capacitor.
 14. A wireless communication devicecomprising: a radio frequency front end including a Lamb wave element, asecond Lamb wave element, a bulk acoustic wave resonator, and a surfaceacoustic wave resonator, the Lamb wave element and the bulk acousticwave resonator implemented on a common substrate of a die, the bulkacoustic wave resonator being included in a band pass filter of amultiplexer arranged to filter a radio frequency signal, the Lamb waveelement being included in a loop circuit, the Lamb wave element coupledto the band pass filter by way of an attenuation element of the loopcircuit, the loop circuit configured to generate an anti-phase signal toa target signal at a particular frequency, the surface acoustic waveresonator being included in a second band pass filter of themultiplexer, and the second Lamb wave element being included in a secondloop circuit coupled in parallel with the second band pass filter; andan antenna in communication with the band pass filter.
 15. The wirelesscommunication device of claim 14 wherein the bulk acoustic waveresonator is a film bulk acoustic wave resonator.
 16. The wirelesscommunication device of claim 15 wherein the common substrate is asilicon substrate and the Lamb wave element includes an aluminum nitridelayer.
 17. A radio frequency module comprising: a first band pass filterconfigured to filter a radio frequency signal, the first band passfilter including a bulk acoustic wave resonator; a second band passfilter including a surface acoustic wave resonator, the first band passfilter and the second band pass filter being included in a multiplexer;a first loop circuit including a first Lamb wave element and a firstattenuation element, the first Lamb wave element coupled to the firstband pass filter by way of the first attenuation element, the first loopcircuit configured to generate an anti-phase signal to a target signalat a particular frequency, and the bulk acoustic wave resonator and thefirst Lamb wave element implemented on a common substrate of a die; asecond loop circuit coupled in parallel with the second band passfilter, the second loop circuit including a second Lamb wave element anda second attenuation element, the second Lamb wave element coupled tothe second band pass filter by way of the second attenuation element;and a radio frequency switch coupled to the first band pass filter, theradio frequency switch arranged to pass the radio frequency signal. 18.The radio frequency module of claim 17 wherein the bulk acoustic waveresonator is a film bulk acoustic wave resonator.
 19. The radiofrequency module of claim 17 wherein the common substrate is a siliconsubstrate.
 20. The radio frequency module of claim 17 wherein the firstLamb wave element includes an aluminum nitride layer.
 21. The radiofrequency module of claim 17 wherein the second Lamb wave element andthe surface acoustic wave resonator are implemented on a commonsubstrate of a second die.